I believe Professional Development begins with a sense of self.
And a strong sense of self begins with Self-Exploration.
Day One: Character Flaws
What negative character flaws do you fear - in your worst nightmares - that other people have spotted about you?
Almost certainly, these flaws are on everyone's radar already. Other people know more about us after five minutes than we tend to know after decades - because their knowledge isn't inhibited by squeamishness. Honesty has no cost for them. Rather than hope no one can see your flaws, assume everyone spotted them long ago - and deal with the prospect by behaving with intelligent modest humor around them.